Mutsy- I just want to add that Rosetta Stone provides online support for many of its language programs for an additional charge. This is a great online English tutor program. It is an immersion program in which the student learns by assimilation. There are six levels in the program and the entire English language set retails for almost $600.
The program is very interactive and builds knowledge in the language by beginning with pictures and later eliminating the pictures and then having the student remember the phrase and write it on the computer.
The program also provides a voice assessment and grades it in comparison to what a native speaker would sound like.
For those that speak the language but need help with other aspects of the English language such as writing and composition, a site called Brave writer might help.
It is an intense writing program geared toward the home school students, but anyone can enroll. There are writing topics along with critiques that help the writing student produce higher quality content.